Radio receiving system



Nov. 15, 1927. 1,649341 1 w. N. FANNING RADIO RECEIVING SYSTEM Filed Feb. 28, 1925 inw/ && ATTORNEYS.

WIT/V556 Patented Nov. 15, 1927.

UNITED STATES WZALTER 'N. FANNING, OF VALLEJO, CALIFORNIA.

RADIO REGEIVIN G SYSTEM.

Application filed February 28, 1923. Serial No. 621,771.

. received telegraphic signals.

Due to the extreme weakness of the currents that are ordinarily induced in receiving systems to Operate translatin devices, it is impossible, without special so emes, to operate an electromagnetic relay in a reliable manner. One may of course utilize a large number of stages of amplification in order to produce a correspondingly large variation in current; but with the available types of thermionic amplifiers, it has been found difficult, if not impossible, to control these amplifiers so that they may cooperate without producing extraneous disturbing effects,

to produce a mechanical movement strong enough for relaying purposes. It is one of the objects ofmy invention to provide a reliable telegraphic relay for radio systems, in which the necessity for many stages of-amplification is entirely obviated.

It is still another object of my invention to, provide a relaying system for radio signals in which but a single receiving circuit is used to affect alternately both coils of a differentially wound relay, as the signals stop and start. In this way the armature is positively moved from one extreme position to the other whenever a signaling impulse is received, as well as when the impulse ceases.

My invention possesses other advantageous features, some of'which, with the foregoing, will be set forth at length in the following description, where I shall outline in full those forms of the invention that I have selected for illustration in the drawings accompanying and formng part of the present specification. Although in the drawings I have shown but a few embodiments of my invention, it is to be understood that I do not desire to be limited thereto, since the inr vent'ion as expressed in the claims, may be embodied in other forms also.

Referring to the drawings: t Figure 1 is a-wiring diagram one form of 'my invention; and

, v Fig. 2 is a wiring diagram of a modified form of the invention.

In Fig. 1 an absorbing. circuit, such as antenna 11, variable inductance 12, and ground 13 is used to afiect a detector circuit in the usual manner. This detector circuit may comprise an inductancel i coupled to illustrating inductance 12, anda variable tuning condenser 15. The reception of a signaling impulse 1n this circuit is caused to move a relay armature 16, say from its extreme right hand position to its extreme left hand position, and thus to control certain contacts. present instance, this movement of armature 16 causes the interruption of a circuit between l1nes 17 and 18, and the completion of fiCII'Clllt between lines 18 and 19; These lines may be appropriately connected. with deslred .recording or repeating devices. The cessation of a signal impulse is also made use of to move the armature 16 positively to its extreme right hand position, and the connection between lines 17, 18 and 19 are conversely aifected.

In order to comprehend how I am enabled to produce these effects, I shallnow proceed to describe in detail the relay control system. I preferably utilize a U-shaped core 20 for the relay 21, upon opposite legs of which produce a magnetomotive force in a direction represented by arrows 24 and 25, and

In the are wound the coils 22 and 23. These coils tend to produce a north pole at the right and a south pole at the left. Since the armature 16 has a north pole at its free end,'it is evident that energization of coils 22 and 23 will cause actuation of armature 16 to the left. This movement is caused not merely by the attraction of the armature 16 to the left, but also by its repulsion from the right. It is thus evident that a much stronger movement of the armature is rendered possible than by the aid of an ordinary non-polarized relay. The "oils 22 and 23 are substantially entirely inactive except when a signaling impulse is received.

For producing this latter efi'ect, I utilize.

a three-electrode thermionic device 26, having a heated filament 27, a control grid 28, and alplate 29. .The input circuit of this device between the grid and filament connects to the receiving circuit 1415,'while the output circuit, between the filament and plate,

constantly energized fwhetlier signalingimpulses be received or not..' The reception of connects to the coils 22"and 23. "This output animpulse would merely cause an increased 1 current flowin this circuit. I eliminate the current flow during periods of non-reception by impressing a negative potential on control grid 28, sufliciently large to bring the output current substantially to zero. For this purpose battery 31 is included in the input circuit. I find that if for instance the output circuit battery 30 is one of 120 volts, then battery 31 should be in the neighborhood of 10 or 15 volts; but of course the exact value to bring the non-reception current to zero may be readily found by appropriate' experiment. Upon the reception of a signaling impulse, the negative potential of grid 28 is decreased, for at least some part of the time, and it permits a substantial amount of current to flow through coils 22 and 23. The armature 16 isthus strongly .pulled to the left. Although the variation in the grid potential takes place at a high frequency, the effect on the inductive plate circuit which includes coils 22 and 23 is to cause a pulsatory direct current to flow.

The use of a negatively charged grid to affect the output circuit including an electromagnetic relay is shown in a co-pending application in my name, entitled Radio receiving system, Serial No. 531,121, filed January 23, 1922. My present invention.

differs however from this earlier filed case, in that a single receiving circuit 14-15 is used for operating all of the coils on the electromagnetic relay 21. On the core 20 of the relay are disposed the coils 32 and 33, the magnetomotive forces of which are opposed, as shown by arrows 34 and 35, to those of coils 22 and 23. Whenever coils 32 and 33 are active, and coils 22 and 23 inactive, the armature 16 is pulled positively to the right, due to the formation of a south pole at the right, and a north pole at the left of armature 16.

The control of coils 32 and 33 is accomplished by the aid of a three-electrode'thermionic device 36, which has a heated filament 37, a control grid 38, and a plate 39. The output circuit from plate 39 to filament,37 includes the battery 30 as well as the two coils 32 and 33. The control grid 38 is so arranged that whenever the grid 28 of the thermionic device 26 is at its maximum negative potential with respect to its filament, corresponding to an inactive condition of the receiving circuit 141 5, this grid 38 is neutral or positive with respect to filament I 37; a substantial amount of current can therefore flow in the output circuit and the coils 32 and 33. However, the potential of grid 38 is reduced substantially as soon as the output circuit for tube 26 is active, and

thus currentceases to flow in coils 32 and 33.

To make the potential of grid 38 respond in this manner to that of grid 28, I may utilize a third thermionic tube 40, having a heated filament 41, a grid 42, anda plate 43. The

input circuit from filament 41 to grid 42 is With the connections as described, the control grid 38 is made to have characteristics oppositethat of grid 39. Although the exact reason why this should happen is not easy of explanation, an attempt will be made to trace out the various E. M. F. relations. Assuming first that signaling impulses are being received in circuit 1415, the potentials of both grids 28 and 42 become less negative or even positive, and a current tends to flow in the output circuit, from plate 43, to filament 41, filament 37, grid 38,

and battery .44. The potential of grid 38 is thus negative with respect to the filament 37, and no current can flow in the output circuit of tube 36. However, as soon as the'signaling impulse ceases, the grids 28 and 42 both return to their former negative potential as regards the filaments 27 and 41, and current ceases to flow in the output circuit just traced. The grid 38 loses its negative charge, and current can again flow through the coils 32 and 33. It is not intended that the foregoing explanation be accepted as strictly accurate theoretically; probably additional phenomena but little understood at the present time are at least partly responsible for the coact-ion between the control grids 28 .and 38, whereby they alternately permit the corresponding output currents to In the foregoing description of. the apparatus it has' been assumed that no compensating wave exists between signaling impulses. If such a Wave exists and exerts an appreciable efi'ect upon the detector circuit,

it may be advisable to utilize another detector circuit responsive to the compensating wave and related to the described arrangement similarly to that shown in my prior application, hereinbefore' identified." The application of that principle to the present arrange ment is evident, and further explanation is unessential. V

In the modification shown in Fig. 1, the tube 40 serves as an agency for correlating the grids 28 and 38. I find that other means may be substituted for the thermionic device to effect the same result, and in Fi 2 I illustrate such a substitute arrangement. In

this case the thermionic device 26, the absorbing circuit 1112- 13, the receiving circuit 1415, andthe relay 21 with its coils are arranged identically as in Fig. 1. The

thermionic device 36 also has its output circuit, including the battery 30 and the relay coils, arranged as before. The input circuit, however, including. filament 37 and grid 38, is arranged diifcrently, and includes a condenser 45 of appreciable size, in the neighborhood of one or two microfarad capacity. This input circuit is branched off from the output circuit of device 26. I find that with this arrangement also, grid 38 has potential characteristics that are opposite to those of grid 28, and in this way the coils 22 and 23 are active alternately with coils 32 and 33. When current is permitted to flow in that branch of the output circuit of tube 26 which includes coils 22 and 23, the grid 38 becomes slightly negative with respect to filament 37. This is quite probably due to the drop in potential through coils 22 and 23, which causes point 46, where the condenser 45 connects, to be at a lower potential than when no current flows in this output circuit. I also find that a variation in the operation may be efiected by reversing the connections for the heating battery 47 this probably has some efiect upon the potential difference between the filament 37 and grid 38.

The operation of both forms of the invention it is believed is clear from the foregoing explanation; The armature 16 will be reciproca-ted between its extreme positions 'at telegraphic speed, and this action is vigorous even when receiving from distant stations. While in the forms shown radio frequency apparatus. is indicated, it is of course obvious that the same principal of operation may be utilized at audio frequencies, such as would be necessary where audio frequency amplification is used.

I claim:

1. In a receiving system, an electronic device having a control electrode, an electron emitting electrode and a plate, a circuit between the electronemitting electrode and the plate, means for impressing a negative potential on the control electrode with respect to the electron emitting electrode so as to reduma the current flow in the circuit substantially to zero, an electronicdevice having an electron emitting electrode, control electrode and plate, said electron emitting electrode and control electrode being connected respectively to the electron emitting electrodev and control electrode of the first device, a third electronic device having an electron emitting electrode, control electrode and plate, the electron emitting electrode and control electrode being connected, respectively, to the electron emitting electrode and plate of the second device, and a source of E. M. F. in the connection between the control electrode of the third device and the plate of the second device, of such value that this device is substantially non-conductive whenever a current is permitted to flow in the circuit connecting the electron emitting electrode and plate of the first device.

electrodes, a differential 2. A relay system comprising in combination a plurality of electron tubes each having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, a difierential relay having a plurality of sets of independent actuating coils with one set of said actuating coils disposed in each of said output circuits, said electron tube circuits being alternately energized in accordance with signal and non-signal intervals for alternately energizing said sets of actuating coils.

3. A relay system comprising in combination a plurality of electron tubes, each having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, a differential relay including a pair of independent sets of actuating coils and a movable armature, one set of said coils being connected in the output circuit of one of said electron tubes and the other set of said coils being connected in the output circuit of another of said electron-tubes, the circuits of said electron tubes being so adjusted' that the output circuits and the actuating coils included'therein are alternately energized during signaling and non-signaling intervals.

4. A relay system comprising in combination a plurality of electron tubes each having grid, filament and plate electrodes, input and output trodes, a difierential relay including a pair of adjacent sets oft actuating coils and a movable armature, one pair of said actuating coils being connected in one of said output circuits and the other pair of said actuating coils being connected in the output circuit of the other of said electron tubes, and means connected in said electron tube circuits for rendering said actuating coils alternately operative to move said armature in opposite directions during signal and non-signal intervals of a telegraphic code.

5. A relay system comprising in combination, a'pluralityof electron tubes each having grid, filament and plate electrodes, input and output circuits interconnecting said relay having a pair of independent sets of actuating coils, and a movable armature arranged to be moved to either of two positions under the action of one or the other of said sets of coils, one set of said coils being arranged in the output circuit of one of said tubes and the other set of said coils being arranged in the output circuit of another of said tubes, connections between the output and input circuits of said last mentioned tubes whereby said set of coils are independently energized during signal and non-signal intervals for moving said armature in opposite directions.

A 6. A relay system comprising in combination, a pair of electron tubes each having grid, filament and plate electrodes, input and output circuits'interconnecting said eleccircuits interconnecting said elec Ill) trodes, a difierential relay including independent sets of actuating coils and a movable armature arranged to be moved in one direc- .tion by the action of one of said sets of coils and in the opposite direction by the action of the other of said sets of coils, connections between the output circuits of each of said tubes and said sets of coils, means for capacitively relating the input circuits of each of said tubes, said electron tube circuits being so adjusted that said sets of actuating coils are alternately energized during signal and non signal intervals of the telegraphic code for moving said armature in opposite directions.

7. A relay system comprising in combination a pair of electron tubes each having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, a differential relay including independent sets of actuating coils and a movable armature, arranged to be moved in one direction by the action of one of said sets of coils and in the opposite direction by the of electron tubes and its output circuit connected to the input eircuitof the other of said pair of electron tubes, and means in the circuits of said electron tubes for alternately energizing and de-energizing said sets of actuating coils during signal and non-signal intervals of a telegraphic code for moving said armature in opposite directions.

In testimony whereof, I have hereunto set my hand.

WALTER N. FANNING. 

